Cast duration to integer in `TimeHelper#time_interval_in_words`

app/helpers/time_helper.rb

 module TimeHelper
   def time_interval_in_words(interval_in_seconds)
+    interval_in_seconds = interval_in_seconds.to_i
     minutes = interval_in_seconds / 60
     seconds = interval_in_seconds - minutes * 60
 

spec/helpers/time_helper_spec.rb

@@ -5,6 +5,7 @@ describe TimeHelper do
     it "returns minutes and seconds" do
       intervals_in_words = {
         100 => "1 minute 40 seconds",
+        100.32 => "1 minute 40 seconds",
         121 => "2 minutes 1 second",
         3721 => "62 minutes 1 second",
         0 => "0 seconds"